LONDON, UNITED KINGDOM Regular users of cannabis demonstrate limited, or in some cases, no impairment on measurements of either cognitive or psychomotor performance, according to data published in the journal Neuroscience and Biobehavioral Reviews.
British researchers conducted a systematic review of all human trials examining whether subjects exhibit tolerance to the effects of cannabis following repeated dosing. Thirty-six trials, involving over 1000 subjects, were included in their review.
Authors reported that repeated exposure to either cannabis or THC was associated with partial or full tolerance in subjects, particularly with regard to cognitive performance and psychomotor abilities.
They reported: Studies indicated relatively minor or no effects of repeated 9-THC administration in RU (regular users) on a number of cognitive domains including learning, memory, vigilance, and psychomotor ability. This absence of effect in RU might indicate the development of full tolerance.
Investigators concluded: Available evidence suggests that the effects of acute marijuana or 9-THC administration are less prominent in individuals with a regular pattern of cannabis use compared to non-regular users. Cognitive function appears ...